Image pickup apparatus (hereinafter simply referred to as a camera) which uses an image pickup element such as a Charge Coupled Device (CCD) image sensor is installed in various sites including outdoor places for the purposes of crime prevention and keeping track of ambient situations and video images taken by the camera are monitored.
When an image pickup element such as CCD is electrified, its temperature rise occurs by heat generated by electricity. If the element's temperature rises excessively, white spots increase or a dark current inside the image pickup element increases and the quality of video images taken deteriorates. For this reason, a performance assurance temperature range is specified for an image pickup element. The camera is equipped with a cooling mechanism to suppress the temperature rise of the image pickup element within the specified range.
Some camera of background art has a structure in which a cooling plate is placed in close contact with an image pickup element and the cooling plate is fixed to the camera hosing. Heat of the image pickup element is thus conducted to the cooling plate and further conducted to the camera hosing, thereby decreasing the increased temperature of the image pickup element. Besides, cooling is also performed with a Peltier element attached to the image pickup element (refer to PTL 1).
However, one side of the Peltier element is cooled, whereas its other side heats up. Hence, the image pickup element is cooled by one side of the Peltier element, but the inside of the camera hosing is heated by the other side of the Peltier element; therefore, it is not easy to improve the efficiency of cooling the entire image pickup element.
Besides, in a case where the camera is used in a low-temperature environment (e.g., around −25° C.) or in a case where the camera is installed in a site where it is forcibly exposed to cold wind at all times, heating measures or the like are needed to make the temperature of the image pickup element fall within the performance assurance temperature range. However, for the structure of the cooling plate of the camera of background art, it is not easy to provide a heating means and perform heating efficiently.